I believe the correct option is B. With multiple steps in the instruction manual, we were unsure of the solution when the wheel detached from the bicycle.
It provides the most details. The steps are not "so many" or "many" as in the other options, but "multiple" - which is more precise, as we know there are few steps, and not hundreds of them. Furthermore, it lets us know there is an instruction manual, and not just any kind of instruction. Also, being unsure of a solution is more specific than just not knowing what to do. Finally, this example specifies the context ("the wheel detached from the bicycle").
